Why are ionic compounds typically brittle?

• A. Because the electrons in ionic compounds are free to move throughout the structure.
• B. Because ionic compounds contain molecules that can easily slide past each other.
• C. Because shifting layers of ions brings like charges next to each other, resulting in strong repulsive forces that cause the crystal to shatter.
• D. Because the ions in ionic compounds are held together by weak van der Waals forces.

Answer: (C)

Verified step by step guidance

1. Understand the structure of ionic compounds: Ionic compounds consist of a regular, repeating three-dimensional lattice of positively and negatively charged ions held together by strong electrostatic forces (ionic bonds).
2. Recognize that in this lattice, ions are arranged so that each positive ion is surrounded by negative ions and vice versa, maximizing attractive forces and minimizing repulsion.
3. Consider what happens when a force is applied to the ionic crystal: layers of ions may shift relative to each other.
4. When layers shift, ions of the same charge can be forced next to each other, causing strong electrostatic repulsion between like charges.
5. This repulsion causes the crystal lattice to break apart suddenly, making ionic compounds brittle rather than malleable or ductile.